rplcr - Simple HTML templating

rplcr.pl

#!/usr/bin/env perl
#
# rplcr: Simple HTML templating using perl
#
# HTML templating in the spirit of "the simplest thing that could possibly work".
#
# Matches lines ending in
#
# <!-- $RPLCR$ some_perl_code_goes_here -->
#
# where some_perl_code_goes_here is arbitrary perl code that gets
# applied to the line.
#
# Example:
#
#   <script src="js/lib.js"></script> <!-- $RPLCR$ s:(js/):$ENV{ASSET_PREFIX}.$1:e -->
#
# Used like this:
#
#   ASSET_PREFIX=my-asset-id rplcr index.html
#
# Or if you want in-place editing:
#
#   ASSET_PREFIX=my-asset-id perl -i rplcr index.html

while (<>) {
    $line = $_;
    if ($line =~ /^(.*)<!--\s+\$RPLCR\$\s+(.*?)-->\s*$/) {
        $content = $1;
        $code = $2;

        $_ = $1;
        eval($code);
        print "$_\n";
    }
    else {
        print $line;
    }
}